1. Field of the Invention
The present invention relates to the field of wireless communication; and more particularly, a method of processing soft handoff information at a base station.
2. Description of Related Art
FIG. 1 illustrates three adjacent cells in a wireless communication system. The communication needs of mobile stations (MSs) in each cell 10 are served by a base station (BS) in the cell. Under certain conditions, such as when the mobile station MS is moving from one cell to another as depicted by the arrow in FIG. 1, the base station BS of the cell 10 containing the mobile station MS hands off communicating with the mobile station MS to another base station BS.
Code Division Multiple Access (CDMA) wireless communication systems involve processing at the mobile station in deciding whether to handoff responsibility for communicating with the mobile station from one base station to another base station. This has been generally referred to as soft handoff.
CDMA standards such as those governing wireless communication in the United States, IS-95A and IS-95B, specify soft handoff processing at the mobile station. The soft handoff processing at the mobile station involves making measurements and precatory determinations as to handoff, but the base station serving the communication needs of the mobile station makes the final decision on handoff. Furthermore, the methodology employed by the base station is not specified in the standards. As a result, a demand exists for base station soft handoff processing methodologies that reduce the percentage of time the mobile station is in handoff without degrading system performance (e.g., reducing system capacity or costing more network resources).